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 June 9th, 2015, 07:39 AM #1 Newbie   Joined: May 2015 From: Portland, OR. USA Posts: 8 Thanks: 0 Expected Value Here are two Expected Value problems. Can somebody please check my answers? 1. In American roulette, the wheel has the 38 numbers, 00, 0, 1, 2, ..., 34, 35, and 36, marked on equally spaced slots. If a player bets \$1 on a number and wins, then the player keeps the dollar and receives an additional \$35. Otherwise, the dollar is lost. 36 * (1/38) + -1 * (37/38) ≈ -.03 (The book says -.05. I don't understand what I did wrong) 2. A charity organization is selling \$5 raffle tickets as part of a fund-raising program. The first prize is a trip to Mexico valued at \$3450, and the second prize is a weekend spa package valued at \$750. The remaining 20 prizes are \$25 gas cards. The number of tickets sold is 6000. 3450 * (1/6000) + 750 * (1/6000) + 25 * (20/6000) + /5 (5987/6000) ≈ -4.2 Last edited by greg1313; June 10th, 2015 at 11:30 AM.
June 10th, 2015, 11:20 AM   #2
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Quote:
 Originally Posted by statssav Here are two Expected Value problems. Can somebody please check my answers? 1. In American roulette, the wheel has the 38 numbers, 00, 0, 1, 2, ..., 34, 35, and 36, marked on equally spaced slots. If a player bets \$1 on a number and wins, then the player keeps the dollar and receives an additional \$35. Otherwise, the dollar is lost. 36 * (1/38) + -1 * (37/38) ≈ -.03 (The book says -.05. I don't understand what I did wrong)
If the question is "what are your expected winnings" then the answer is

$\displaystyle 35 \cdot \frac{1}{38} + (-1) \cdot \frac{37}{38} = \frac{-2}{38}$.

,

## a charity organization is selling $5 raffle tickets as part , # a charity organization is selling$5 raffle

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